The present invention relates to an ignition coil for motor vehicles, comprising a single output terminal, designed to be mounted directly on the end portion of a corresponding spark plug. Coils of this type comprise a body carrying at one end a flexible cap provided with a seat designed to receive the end of a spark plug. The cap comprises a high-voltage terminal electrically connected to the high-voltage winding of the coil and provided with a connection portion designed to receive a terminal of the plug.
Spark plugs of the type specified above, provided with a diode connected in series between the high-voltage winding and the high-voltage terminal of the coil are known. The use of a high-voltage diode in a single-output coil has the peculiar function of eliminating the overvoltages generated by the oscillations of the primary current at the start of the charging cycle. These overvoltages may cause undesired pre-ignition. In coils of the known type, the high-voltage diode is set inside the coil body.
The aim of the present invention is to provide an ignition coil of the type described above that is simpler from the constructional standpoint, more reliable, and of smaller dimensions than known coils.
According to the present invention the above purpose is achieved by an ignition coil having the characteristics that form the subject of the main claim.